Process for the production of modified cationic emulsion polymers with cationic polyurethane

ABSTRACT

A process is provided for the production of stable aqueous polymer dispersions by subjecting vinyl monomers to radical emulsion polymerization in the presence of a stable aqueous dispersion of a high molecular weight cationic polyurethane which is gel-like in character.

United States Patent Honig et al.

[54] PROCESS FOR THE PRODUCTION OF MODIFIED CATIONIC EMULSION POLYMERSWITH CATIONIC POLYURETHANE [72] Inventors: Hans Ludwig Honig,Leverkusen;

Carlhans Suling, Odenthal-Hahnenberg; Dieter Dieterich; Artur Reischl,both of Leverkusen, all of Germany [73] Assignee: Farbenfabriken BayerAktiengesellschaft, Leverkusen, Germany [22] Filed: Oct. 21, 1970 [21]Appl. No.: 82,795

[30] Foreign Application Priority Data Oct. 23, 1969 Germany ..P 19 53345.0

[52] US. Cl ..260/29.6 NR, 117/161 RP, 260/29.4 UA, 260/29.7 NR, 260/859R, 260/859 PV 51 Aug. 15, 1972 [51] Int. Cl. ..C08f 45/24 [58] Field ofSearch...260/29.6 NR, 29.4 UA, 859 R, 260/859 PV [56] References CitedUNITED STATES PATENTS 5/1966 von Bonin et al ..260/874 6/1968 Dieterichet al....260/29.2 TN Ill 1970 Keberle et al ..260/29.6 NR

Primary Examiner-Harold D. Anderson Attorney-Robert A. Gerlach andSylvia Gosztonyi ABSTRACT 8 Claims, No Drawings PROCESS FOR THEPRODUCTION OF MODIFIED CATIONIC EMULSION POLYMERS WITH CATIONICPOLYURETHANE Aqueous emulsions of polyurethanes containing blocks ofvinyl polymers can be obtained by copolymerizing vinyl monomers withpolyurethanes having terminal vinyl groups in an aqueousemulsifiercontaining medium. Unfortunately, this process is complicatedin the preparation of the polyurethane since a prepolymer containingterminal isocyanate groups is reacted at one end of the chain with avinyl monomer containing an active hydrogen atom, for examplehydroxyethyl acrylate, while chain extension is effected via the secondisocyanate group with the result that a polyurethane containing twoterminal vinyl groups is formed. This polyurethane is dissolved in oneor more vinyl monomers and the resulting mixture is subjected to radicalpolymerization in an aqueous medium in the presence of an emulsifier.

It is also known that olefins, olefins with nitrogencontaining groups orvinyl esters can be radically grafted onto polyalkylene glycols eitherin bulk or in solution when the terminal hydroxyl groups of the glycolhave been reacted with diisocyanates as described in German Pats. Nos.1,077,430 and 1,105,179.

The radical polymerization of vinyl or vinylidene compounds ontopolyacetals containing urethane groups is described in U.S. Pat. No.3,249,654.

Finally, it has also been proposed to employ high molecular weightcationic polyurethanes containing quaternary ammonium or tertiarysulphonium groups as emulsifiers for polymerization reactions asdescribed in U.S. Pat. No. 3,388,087.

it is therefore an object of this invention to provide stable aqueouspolymer dispersions and a method for preparing them which are devoid ofthe foregoing disadvantages.

Another object of this invention is to provide a process for theproduction of stable aqueous polymer dispersions in the presence ofgeHike particles which serve as a grafting substrate.

A further object of this invention is to provide stable aqueous polymerdispersions and a method for preparing them which does not require thepresence of an emulsifier.

A still further object of this invention is to provide stable aqueouspolymer dispersions which are eminently suitable as coatingcompositions, adhesives and binders with excellent adhesive propertiesthe ultimate hardness and flexibility of which can be easily adjusted ifdesired.

The foregoing objects and others which will become apparent from thefollowing description are accomplished in accordance with thisinvention, generally speaking, by providing a process for the productionof stable aqueous polymer dispersions which comprises polymerizing 5 95percent by weight based on the total amount of non aqueous matter ofolefinically unsaturated monomers under radical emulsion polymerizationconditions in the presence of 95 5 percent by weight based on the totalamount of non aqueous matter of a cationic polyurethane having amolecular weight of at least 20,000 and containing from about 0.05 toabout 5 percent by weight of ammoniumor sulphonium groups whichpolyurethane is gel-like in character and which is present in the formof a stable aqueous dispersion.

More particularly, the process :is carried out by stirring an aqueousemulsion of the cationic polyurethane with a radically polymerizablevinyl monomer or monomer mixture and carrying; out polymerization underconventional emulsion polymerization conditions as described in Methodender Organischen Chemie Houben-Weyl Vol. 14/1, 4th edition, pages133-560. The vinyl monomer may be added either all at once, or initiallyin part only, the remainder being added during the reaction.

The cationic polyurethane from which the dispersions suitable for use inthe process of this invention are prepared contain ammonium orsulphonium groups and can be obtained by methods known per se fromrelatively high molecular weight compounds having reactive hydrogenatoms and molecular weights of from 300 to 20,000, organicpolyisocyanates and, optionally, chain extenders containing reactivehydrogen atoms. It is essential, however, to employ from 0.5 to 10percent of a cross-linking agent which may be a trior tetrafunctionalpolyol, polyamine or polyisocyanate or may be an agent which has across-linking effect such as a polyfunctional alkylating agent, aprimary diamine which is in fact trior tetrafunctional towardsisocyanate groups; excess of any usual diisocyanate which means anNCO/OH NH ratio from about 1.01 to about 1.6; formaldehyde orderivatives thereof. 1f the crosslinking agent is a polyesterpolyol orpolyetherpolyol having a molecular weight above 800 the given percentagerefers only to the polyfunctional monomer component which is in mostcases trimethylolethane, trimethylolpropane, pentaerythrital orsorbitol. Such cross-linking agents are listed for instance in U.S.Pats. Nos. 3,201,372, 3,350,362, 3,479,310, 3,384,606, 3,410,187.

Some specific examples for cross-linking agents are the following:glycerol, trimethylolethane, trimethylolpropane, trifunctionalpolyetherpolyols which are oxalkylation products of the foresaidcompounds, triethanolamine, water, diethylenetriamine,l.2.4benzene-tricarboxylic acid, the trimerisation product of adiisocyanate such as toluylen-2,4-diisocyanate or of mixtures oftoluylendiisocyanate and hexamethylene-l,6-diisocyanate, or any otherpolyisocyanate containing more than two isocyanate groups, ethylenediamine, hexamethylene diamine, N-methyl-bis-3-aminopropylamine, 1,4-dibromobutane, 1 .3-bisch1oromethy1-4.6-dimethylbenzene,N,N,N',N-tetramethylethylenediamine, sulfun'c acid, phosphoric acid,formaldehyde, melaminehexamethylolhexamethylether. Preferredcross-linking agents are diisocyanates when used in excess overisocyanate-reactive groups, the cross-linking effect being due toformation of biurets or allophanates.

Any of the known and conventionally employed compounds having at leasttwo reactive hydrogen atoms and a molecular weight of from 300 to20,000, organic polyisocyanates and optionally chain extending agentscontaining reactive hydrogen atoms may be used. Examples of thesecomponents can be found in U.S. Pat. No. 3,479,310; U.S. Pat.application, Ser. No. 867,931, filed on Oct. 20, 1969, GermanAuslegeschrift No. 1,067,678 and U.S. Pats. Nos. 3,201,372 and3,350,362.

The aqueous polyurethane dispersions to be used in the process of thisinvention should possess the followmg properties:

1. The polyurethanes should have an average molecular weight in excessof about 20,000, and preferably in excess of about 100,000.

2. The individual latex particles should be gel-like in character; asample of the latex (dispersion) should not dissolve to form a clearsolution in tetrahydrofuran.

Because the latex particles must be gel-like in character, they do notexert an emulsifying effect since emulsifiers must be soluble anddiffusible, i.e. uncrosslinked. On the other hand, these gel particlesserve as an ideal grafting substrate since they are able to absorbconsiderable quantities of monomers, swelling as they do so.

Examples of suitable methods for preparing the aqueous polyurethanedispersions to be used in the practice of this invention can be found inBelgian Pats. Nos. 653,223; 658,026; and 730,543; in published DutchSpecification No. 67 03,743; and in German Auslegeschrifts Nos.1,187,012; 1,184,946; 1,178,586 and 1,179,363. Polyurethane dispersionscontaining from about 0.05 to about5 percent of ammonium or sulphoniumgroups as cationic groups are particularly suitable for use in thepractice of this invention.

In principle, any radically polymerizable monovinyl and polyvinylcompounds and mixtures thereof may be used as the vinyl monomers in thepractice of this invention including any of those listed in U.S. Pat.No. 3,225,119. Some examples of suitable compounds include:

l. Esters of a,b-unsaturated carboxylic acids such as, for example,methyl methacrylate, ethyl acrylate, butyl acrylate, stearylmethacrylate, hydroxypropyl acrylate, 2-aminoehtyl methacrylatehydrochloride, dimethylaminoethyl methacrylate, methoxymethylmethacrylate, chloromethyl methacrylate, dichlorotriazinyl-aminoethylmethacrylate, esters of maleic acid, fumaric acid or itaconic acid andthe like;

2. a,b-unsaturated carboxylic acids such as, for example, acrylic acid,methacrylic acid, maleic acid and the like;

3. Amides of a,b-unsaturated carboxylic acids such as, for example,acrylamide, methacrylamide, maleic acid amide, maleic acid imide and thelike;

4. Substituted amides of unsaturated carboxylic acids such as, forexample, methylol methacrylamide, methoxymethyl acrylamide, N-(methylacrylamidomethyl)-urethane, N- chloroacetamidomethyl)-acrylamideand the like;

5. Nitriles of a,b-unsaturated carboxylic acids such as, for example,acrylonitrile, methacrylonitrile and the like;

6. Vinyl esters such as, for example, vinyl acetate,

vinyl chloroacetate, vinyl chloride and the like;

7. Vinyl ethers such as, for example, vinyl ethyl ether and the like;

8. Vinyl ketones such as, for example, vinyl methyl ketone and the like;

9. Vinyl amides such as, for example, vinyl fonnamide, vinyl acetamideand the like;

10. Aromatic vinyl compounds such as, for example,

styrene, vinyl toluene and the like;

1 l. Heterocyclic vinyl compounds such as, for exam ple, vinyl pyridine,vinyl pyrrolidone and the like;

12. Vinylidene compounds such as, for example,

vinylidene chloride and the like;

13. Divinyl compounds such as, for example, divinyl benzene, butane dioldimethacrylate and the like;

14. Monoolefins such as, for example, ethylene,

propylene and the like;

15. Conjugated diolefins such as, for example, bu-

tadiene, isoprene, 2-chlorobutadiene and the like;

16. Allyl compounds such as, for example, allyl acetate, allyl alcoholand the like.

Any suitable polymerization catalysts may be used including inorganicperoxidic compounds such as potassium or ammonium persulphate, hydrogenperoxide or percarbonates; organic peroxidic compounds, such as acylperoxides including, for example, benzoyl peroxide; alkylhydroperoxides, such as tert-butyl hydroperoxide, cumene hydroperoxideand p-methane hydroperoxide; dialkyl peroxides such as di-tert-butylperoxide; peroxy esters such as tert-butyl perbenzoate and the like andmixtures thereof. The organic or inorganic peroxidic compounds areadvantageously used in combination with any suitable reducing agentsknown per se, including sodium pyrosulphite or bisulphite, sodiumformaldehyde sulphoxylate, triethanolamine, tetraethylene pentamine andthe like. Also azo compounds such as azoisobutyronitril, azoisobutyricacid ethylester, azoisobutyroamidine,4,44-cyanovaleric acid and the likeare particularly suitable. The initiators which decompose into radicalsmay be used alone or in combination with reducing agents or heavy metalcompounds. Sodium pyrosulphite, potassium pyrosulphite, formic acid,ascorbic acid, hydrazine derivatives, amine derivatives and rongaliteare examples of reducing agents. The heavy metal compounds may bepresent either in an oil soluble or in a water soluble form. Watersoluble heavy metal compounds include for example silver nitrate,halides or sulphates of divalent or trivalent iron, cobalt or nickel orsalts of titanium or vanadium of lower valences state. Examples of oilsoluble heavy metal compounds are cobaltnaphthenate and the acetylacetone complexes of vanadium, cobalt, titanium, nickel or iron.Preferred initiator systems are combinations of oxidizing agents withreducing agents such as combinations of above peroxides or inorganicoxidizing agents such as metal chlorates, metal chlorides or metalhypochlorites with reducing agents such as hydrazine, hydroxyl amine andespecially compounds of the divalent or tetravalent sulfur such as metalsulphites, metal sulphides, metal thiosulphates and especiallysulphinates such as sodium hydroxymethyl sulphinate.

The catalysts are employed in the catalytic quantities normally used toinitiate polymerization reactions of this kind, i.e. in quantities offrom about 0.01 to about 5 preferably 0.02 to 1 percent by weight, basedon the total weight of the monomer.

The usual regulators such as long-chain alkyl mercaptans, diisopropylxanthogenate, nitro compounds or organic halogen compounds, may also beused during polymerization to influence molecular weight. The regulatormay optionally be used in amounts of from 0.05 to 5 percent by weightbased on the monomers.

Typical examples are nitro compounds such as ,8- nitrostyrene,panitroaniline, benzal-p-nitraniline, halogen containing compounds suchas tetraiodomethane, iodoform, benzyliodide, allyliodide,N-chlorophtalimide, tribromomethane, l l l tribromo-2-methyl-propanol-2,mecaptanes such as ndodezylmercaptane, tetradezylmercaptane,diisopropylxantogendisulphide etc.

The polymerization temperatures are governed both by the type of monomerused and the activation system employed, but generally range from about0 to about 150C., and preferably from about 30 to about 100C.

Any suitable cationic or non-ionic emulsifiers, or combinations thereofmay be used as emulsifiers including cationic emulsifiers such as saltsof quaternary ammonium and pyridinium compounds. Typical exam ples ofsuitable emulsifiers are salts of C, C -amines such as salts of alkyl-,aryl-, arylalkylor alkyla rylamines with inorganic or organic acids.Representatives of these compounds are e.g. N-dodecylamoniumsulphate,N-hexadecyl ammoniumbenzenesulphonate, N-( l0-phenyl-decyl)-ammoniumsulphate etc. Further examples of suitable cationic emulsifiers arelisted e.g. in Journal of the American Oil Chemical Society 43, (1966),pages 681-682. The known reaction products of ethylene oxide withlong-chain fatty alcohols or phenols may be used as nonionic emulsifiersand the reaction products of more than mols of ethylene oxide with 1 molof a fatty alcohol or phenol are particularly suitable. A total quantityof up to about percent by weight of the emulsifiers based on the totalmonomer component may be used but preferably from about 2 percent toabout 10 percent by weight is employed. However, the emulsionpolymerization reaction may be carried out in the absence ofemulsifiers, if desired.

The cationic polyurethanes and the monomers to be polymerized may bepresent at any ratio in the reaction mixture; however, from about 5percent to about 95 percent by weight of dry cationic polyurethane toabout 95 percent to about 5 percent by weight of the monomer ispreferred. Most preferred are mixtures of 20 80 percent by weight ofpolyurethane and 80 20 percent by weight of olefinic monomer. Thepolyurethanes are used in the form of their aqueous dispersions andusually have a solids content of from about 5 percent to about 60percent by weight, preferably from about 8 to about 35 percent byweight. It is especially preferred to use at least 20 percent by weightof a cationic polyurethane and up to 80 percent by weight of aolefinically unsaturated monomers.

The process of the invention is carried out under radical emulsionpolymerization conditions. This means 1. the polymerization is carriedout in an aqueous phase;

2. the polymerization is carried out in the presence of emulsifyingagents for the starting as well as for the end-products whichemulsifying agent in the case of the present invention consists eithersolely of the cationic polyurethane salt or of a combination of thecationic polyurethane salt with an other emulsifying agent;

this means 3. the polymerization is carried out in the presence ofradical initiating catalysts at a temperature such to activate thesecatalysts.

In many instances, the polymers initially used and the polymers graftedthereto undergo chemical reaction in which the degree of grafting isgoverned by the type of monomers used, the catalysts employed and thepolymerization conditions utilized.

In polyurethane dispersions prepared without emulsifiers and without anygrafted vinyl components, salt groups take over the function of theemulsifier. These dispersions are distinguished by many interestingservice properties including the fact that they can be processed intofilms of outstanding mechanical strength. Unfortunately, a seriousdisadvantage of these dispersions is the fact that the salt groupsincorporated therein render the polyurethane hydrophilic to a limitedextent so that the films prepared therefrom swell in water or even aredegraded by hydrolysis By contrast, the films obtained from the vinylpolymerpolyurethane dispersions of this invention have a markedlyreduced tendency to swell in water, especially if they are preparedwithout using an additional emulsifier.

The polyurethane dispersions of this invention may be used as coatingcompositions, the ultimate hardness and flexibility of which can beadjusted as required by a judicious selection of the startingcomponents. In the area of coatings, adhesives, binders, e. g. fornon-woven fabrics, glass fibers and the like the products of theinvention are particularly useful, because of their excellent adhesiveproperties which is probably due to the cationic character of theproducts and more specifically to the combination of polar cationicsalt-groups and urethane or urea groups which'are capable of forminghydrogen bonds on the one hand and hydrophobic grouping of the vinyltype as well as the polyester or polyether type on the other hand.Adhesive properties are especially good on substrates having anelectronegative charge such as textiles, paper, heather and glass.

The invention is further illustrated but is not intended to be limitedby the following examples in which all parts and percentages are byweight unless otherwise specified.

The following polyurethane dispersions, for example, may be used in theprocess of this invention.

POLYURETHANE DISPERSION I About 260 parts of a polythioether having anOH number of 71.5 and prepared from about parts of thiodiglycol andabout 30 parts of 1,6-hexane diol are stirred for about 50 minutes atabout C. with about 530 parts of tolylene diisocyanate (isomer mixture65:35). In the meantime, about 8 parts of trimethylol propane areintroduced followed, after cooling to about 45C., by the successiveaddition of about 350 ml of acetone, about parts of diethylene glycol,about 68 parts of hexane-1,6-diol and about 78 parts of N- methyldiethanolamine in about 512 ml of acetone. The mixture is stirred forabout one hour at about 50C., followed by the addition of about 9.5 mlof dimethyl sulphate, about 5.4 parts ofl,3-dimethyl-4,6-bischloromethyl benzene and about 563 ml of acetone,after which the mixture is stirred for another 2 hours at about 50C.About 8 ml of about an 85 percent aque ous phosphoric acid solution inabout 60 ml of water are then added followed by the addition at 70C. ofabout 1,160 ml of water. The acetone is then distilled off in a waterjet vacuum.

About 2,350 parts of about a 48 percent latex are obtained which, afterstanding for 10 days at room temperature, is no longer soluble intetrahydrofuran but can only be mixed with it accompanied by hazing.

POLYURETHANE DISPERSION II About 2,600 parts of a polyether (OH number78) obtained from about 70 parts of thiodiglycol and about 30 parts of1,6-hexane diol are stirred for about 50 minutes at about 80C. withabout 25,300 parts of tolylene diisocyanate (isomer mixture 65:35).Thereafter, the successive addition of about 1,040 parts of diethyleneglycol over a period of about 13 minutes, about 1,400 parts of1,4-butane diol over a period of about 30 minutes and a solution ofabout 780 parts of N-methyl diethanolamine in about 5.1 liters ofacetone is carried out while cooling so that a temperature of from about50 to about 60C. is maintained. A solution of about 126 parts ofdimethyl sulphate and about 54 parts ofl,3-dimethyl-4,6-bis-chloromethyl benzene in about 280 ml of acetone isthen added. After about 6.3 liters of acetone are added, stirring iscontinued at about 50C. until a viscosity of from about 200 to about 500poises has been obtained. The solution is then very thick and hazy andcannot be further diluted with acetone. About 135 parts ofabout an 85percent phosphoric acid solution, about 110 parts of triethyl phosphatein about 640 ml of water, and about 1 1.6 liters of water are thensuccessively stirred in. The acetone is then distilled off in a waterjet vacuum.

About 22 liters of about a 50 percent polyurethane latex which is thinlyliquid are obtained which, after storage for several days, is no longersoluble in tetrahydrofuran but can only be mixed with it accompanied byhazing.

POLYURETHANE DISPERSION 111 About 25,000 parts of a polyester (OH number64) obtained from adipic acid, phthalic acid and ethylene glycol (molarratio l:l:1.2) and about 6,480 parts of tolylene diisocyanate (isomermixture 65:35) are stirred for about 2 hours at about 70C. About 10.4liters of dimethyl formamide are added to the prepolymer thus formed,followed by the introduction of about 2,600 parts of N-methyldiethanolamine and another 5.2 liters of dimethyl formamide whilecooling. About 105 parts of dibutylamine in about 260 ml of dimethylformamide are then added. A solution of about 780 parts ofl,3-dimethyl-4,6-bis-chloromethyl benzene is then added at about 50C.,followed about 10 minutes later by the introduction of a solution ofabout 765 parts of about an 85 percent phosphoric acid solution in about3.1 liters of water. The product is then diluted with about 237.8 litersof water at about 50C. and about 30 liters of dimethyl formamide.

About a 29 percent dimethyl formamide-water polyurethane dispersion isobtained which remains hazy when diluted with tetrahydrofuran, thusindicating that it consists of gel-like latex particles.

EXAMPLE 1 About 20 parts of a mixture of about 60 parts of butylacrylate, about 40 parts of acrylonitrile, about 0.5 part of cumenehydroperoxide, and about 10 parts of a solution of about 0.1 part ofsodium formaldehyde sulphoxylate in about 50 parts of water are added tobatches of about 450 parts of each of Polyurethane Dispersions I, II andIII while stirring in a nitrogen atmosphere at about 50C., and dilutedwith water to a solids content of about 8 per cent. The rest of themonomer mixture consisting of parts of the above mixture of 60 pans ofbutylacrylate and 40 parts of acrylonitrile and the sulphoxylatesolution are then successively added dropwise to the reaction mixtureuniformly over a period of about 2 hours and the complete mixture isstirred for about 5 hours at about 50C. Polymer dispersions which yieldcoherent tearresistant films when dried on glass plates and which have asolids content of from about 22 percent to about 23 percent are thusobtained.

EXAMPLE 2 Films are prepared from Polyurethane Dispersion 111 as well asPolyurethane Dispersion III modified with a copolymer of butyl acrylateand acrylonitrile as described in Example 1 by drying these dispersionson glass plates in air at room temperature, and storing the air-driedfilms in water for about 16 hours at room temperature. While the filmobtained from pure Polyurethane Dispersion IIl increases in weight byabout 80 percent of its original weight, the water absorption of themodified polyurethane film is only about 30 percent.

EXAMPLE 3 About 139 parts of about a 29 per cent Polyurethane DispersionIII are diluted with about 161 parts of water and a mixture of about 60parts of styrene, about 0.4 part of cumene hydroperoxide and a solutionof about 0.1 part of sodium formaldehyde sulphoxylate in about 40 partsof water are successively added dropwise to the resulting mixture whilestirring in a nitrogen atmosphere over a period of about 2 hours atabout 50C., followed by stirring for about 1 hour.

A stable polymer dispersion having a solids content of about 25 percentis thus obtained. A hard polymer film is produced when the polymerdispersion is dried on a glass plate.

EXAMPLE 4 Stable 25 percent copolyurethane dispersions are prepared asdescribed in Example 3 from monomer mixtures of (I) about 45 parts ofbutyl acrylate and about 15 parts of vinyl acetate and (2) about 45parts of butyl acrylate and about 15 parts of vinylidene chloride. Thesedispersions yield soft, elastic films when dried on glass plates.

EXAMPLE 5 About 3,000 cc. of polyurethane III, about 3,000 cc. ofdesalted water and about 300 parts of vinyl chloride are stirred andemulsified at about 5C. in a polymerization vessel. Equal quantities of:

l. a mixture of about 200 cc. of water and about 5 parts of 30 per centH and 2. a solution of about 10 parts of sodium formaldehydesulphoxylate in about 100 cc. of water are then separately introducedover a period of about 30 minutes into the stirred emulsion. Thereaction mixture is kept at about 5C. during polymerization which isterminated after about 5 hours. The emulsion reaction product is freedfrom excess monomer in a gas separator and adjusted in vacuo to a solidscontent of about 25 percent. The resulting concentrated emulsion isstable and yields elastic films when dried on glass plates. A polymersample contains about 2 percent of Cl after precipitation with a mixtureof methanol, ammonia and water (90:2:8).

EXAMPLE 6 The procedure described in Example 4 is carried out exceptthat a mixture of about 100 cc. of water and about 10 parts oftert-butyl hydroperoxide is used in stead of the l-l O -water mixture. Astable emulsion is again obtained; however, a precipitated polymersample has a chlorine content of 6.9 percent.

It is to be understood that any of the components and conditionsmentioned as suitable herein can be substituted for its counterpart inthe foregoing examples and that although the invention has beendescribed in considerable detail in the foregoing, such detail is solelyfor the purpose of illustration. Variations can be made in the inventionby those skilled in the art without departing from the spirit and scopeof the invention except as is set forth in the claims.

What is claimed is:

l. A process for the production of stable aqueous polymer dispersionswhich comprises polymerizing 5 to 95 percent by weight based on thetotal amount of nonaqueous matter of olefinically unsaturated monomersunder free radical emulsion polymerization conditions in the presence ofto 5 percent by weight based on the total amount of non-aqueous matterof a cationic polyurethane prepared by reacting an organic polyisocyanate with an organic compound having at least two hydrogen atomsreactive with NCO groups and from about 0.5 to about 10 percent byweight of all of the reactants of the polyurethane reaction mixture of across-linking agent, which cationic polyurethane contains from about0.05 to about 5 percent by weight of ammoniumor sulphonium groups, isgel-like in character, insoluble in tetrahydrofuran and present in theform of a stable aqueous dispersion.

2. The process of claim 1 wherein the radical emulsion polymerization iscarried out in the presence of an inorganic peroxide, an organicperoxide, an alkyl hydroperoxide, a dialkyl peroxide, a peroxy ester ormixtures thereof as catalysts.

3. The process of claim 2 wherein the catalysts are present inquantities of from 0.01 to about 5 percent by weight based on the totalweight of the vinyl monomer.

4. The process of claim 1 wherein the radical emulsion polymerization iscarried out at a temperature of from about 0 to about C.

5. The process of claim 1 wherein the reaction mixture contains anemulsifier.

6. The process of claim 1 wherein the polyurethane is ra tee: Emit2%???82 5?? 3llt weight.

7. The process of claim 1 wherein the cationic polyurethanecross-linking agent is a trifunctional polyol or a polyisocyanate.

8. The stable aqueous polymer dispersion prepared by the process ofclaim 1.

2. The process of claim 1 wherein the radical emulsion polymerization is carried out in the presence of an inorganic peroxide, an organic peroxide, an alkyl hydroperoxide, a dialkyl peroxide, a peroxy ester or mixtures thereof as catalysts.
 3. The process of claim 2 wherein the catalysts are present in quantities of from 0.01 to about 5 percent by weight based on the total weight of the vinyl monomer.
 4. The process of claim 1 wherein the radical emulsion polymerization is carried out at a temperature of from about 0* to about 150*C.
 5. The process of claim 1 wherein the reaction mixture contains an emulsifier.
 6. The process of claim 1 wherein the polyurethane is present in the form of an aqueous dispersion having a solids content of from about 5 to about 60 percent by weight.
 7. The process of claim 1 wherein the cationic polyurethane cross-linking agent is a trifunctional polyol or a polyisocyanate.
 8. The stable aqueous polymer dispersion prepared by the process of claim
 1. 